System Outline
WARNING: This page is about a different car, the 2008 Lexus IS F. However, it is still accessible from the selected car via links, so may be relevant.
* To reduce the steering effort, the amount of steering assistance required is calculated according to the torque sensor signals and the vehicle speed. The required steering assistance is then output to the motor.
* When an abnormality is found in the system, the power and motor relays (Built into the ECU) are shut off to stop the assistance and the power steering warning light on the combination meter illuminates.